The present invention relates to a lubricating oil which is applied to the surface of a die during warm forging, hot forging, rolling, tube-manufacturing, drawing or extruding a material such as carbon steels, special steels or non-ferrous metals and which can be substituted for the graphite-containing lubricating oils and is effective for the improvement of working surroundings.
When the foregoing materials are subjected to various processing such as warm forging, hot forging, rolling, tube-manufacturing, drawing and extrusion, there have exclusively been employed lubricating oils to be supplied to the surface of a die during processing, which comprise graphite dispersed in oils or water. The lubricating oils comprising graphite dispersed in oils are excellent in lubricity, but have insufficient abilities of cooling dies. On the other hand, the lubricants comprising graphite dispersed in water have excellent abilities of cooling dies, but is insufficient in lubricity. For this reason, they are properly selected depending on the process conditions and put into practical use. In addition, either of these lubricants are black in appearance and correspondingly, suffer from a problem of dirt of working surroundings.